Analysis by: Jennifer Gumban
ALIASES:

a variant of Win32/Korplug.EG trojan (NOD32)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes commands from a remote malicious user, effectively compromising the affected system.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 3,584 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 01 Aug 2016
Payload: Connects to URLs/IPs

Arrival Details

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This backdoor drops the following files:

  • %Program Files%\Common Files\McAfee\McAfee.exe ← normal file used to load msi.dll
  • %Program Files%\Common Files\McAfee\McUtil.dll ← copy of itself, detected as BKDR_PLUGX.EAJ
  • %Program Files%\Common Files\McAfee\McUtil.dll.mc ← config data; detected as BKDR_PLUGX.EAJ

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

It adds the following processes:

  • %System%\svchost

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It injects itself into the following processes running in the affected system's memory:

  • svchost.exe

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Manage files, registries, services and directories
  • Log keystrokes and active window
  • Restart/Reboot/Shutdown system
  • Enumerate processes
  • Terminate processes
  • Get drive information
  • Enumerate network resources
  • Set TCP connection state
  • Lock workstation
  • Display a message box
  • Perfrom port mapping
  • Capture screen
  • Perform remote shell

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://air.{BLOCKED}n.org/{random values}

Dropping Routine

This backdoor drops the following files:

  • %Program Files%\Common Files\McAfee\{random file name 1} → encrypted data
  • %Program Files%\Common Files\McAfee\{random file name 2} → encrypted data

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

Other Details

This backdoor deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.708.04
FIRST VSAPI PATTERN DATE: 11 Aug 2016

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Program Files%\Common Files\McAfee

Step 5

Scan your computer with your Trend Micro product to delete files detected as BKDR_PLUGX.EAJ. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_PLUGX.EAJ. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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